A nucleosome is the basic repEAting unit of chromatin in which 146 base pairs of DNA wrap twice around a histone octamer consisting of two copies of EAch of the core histones, H2A, H2B, H3, and H4.1 The combination of two H2A/H2B dimers and one H3/H4 tetramer crEAte the nucleosome core.2 Histone H3 undergoes many modifications which include acetylation, methylation, and phosphorylation that are important for regulation of gene transcription.1Technical InformationSynonymsHeLa Core HistonesPurity95% estimated by SDS-PAGESourceHighly purified mixture of human core histones (H2A, H2B, H3, and H4) isolated via hydroxyapatite chromatography from HeLa S3 (human cervical adenocarcinoma) nuclEAr pelletFormulation50 mM sodium phosphate, pH 6.9, containing 10 mM sodium chloride and 1 mM -mercaptoethanol